That's interesting. I only read your highlights so far. I seem to remember reading an article or sniplet recently on this subject that suggested there were fibers that were neither fast nor slow twitch but that had the potential to be either one based on training. I'm unsure of the validity of that, or how elastic their potential is after differentiation (assuming that this occurs at all).
"Use what talents you possess: the woods would be very silent if no birds sang there except those that sang best." —Henry Van Dyke